The American College of Surgeons (ACS) has established the American College of Surgeons Oncology Group (ACSOG) to conduct multicenter cooperative group trials designed to evaluate the role of surgical procedures in the treatment of patients with malignant solid tumors. The existence of a surgical clinical trial group is important to the oncological community because of the primary role of surgery in the treatment of the cancer patient. The trials will also evaluate the utility of selected new operations, technology, and instrumentation as they are introduced into clinical practice. Furthermore, the ACSOG will perform trials that are based on new basic science discoveries; specifically (a) the evaluation of new molecular markers in the diagnosis and treatment of the cancer patient and (b) the place of interventional therapy in patients demonstrated to have a genetic predisposition for cancer. Through its substantial education and communication programs the ACS will place great emphasis on the education of surgeons in clinical trial methodology and in the importance of their participation in the ACSOG clinical trials programs. The ACS is the largest organization of surgeons in the world with broad geographic membership distribution, including general surgeons and speciality surgeons in both academic medical centers and the private practice community. Furthermore, the Commission on Cancer (COC), of the ACS through the Approvals, Education, Cancer Liaison and National Cancer Database Programs has a large number of active professional staff and volunteers that serve and interact with the Cancer Programs and the practicing surgeons in the 1500 approved hospitals throughout the United States of America and Canada. The ACSOG is committed to performing clinical trials of patients with the most commonly occurring malignant solid tumors. This is evidenced b the concentration of the initial trials on patients with breast cancer, lung cancer and colorectal cancer. The performance of these trials will require a broad base of practicing surgeons in North America and this group of participants is well represented within the membership of the ACS.